Author Topic: Magnavox Hepplewhite  (Read 3601 times)

Offline 19and41

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Magnavox Hepplewhite
« on: December 11, 2015, 03:30:51 PM »
I just got my first console radio, a 1947 Magnavox 153B.  It has an AM and shortwave receiver with an optional FM tuner in a album cabinet.
« Last Edit: December 12, 2015, 11:14:15 AM by 19and41 »
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Offline andre_janew

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Re: Magnavox Hepplewhite
« Reply #1 on: December 11, 2015, 05:23:04 PM »
I didn't realize they had FM radio in 1947!

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #2 on: December 11, 2015, 05:34:19 PM »
The FM process was patented in 1933.  Here is a summary of it's early history.

https://en.wikipedia.org/wiki/FM_broadcasting_in_the_United_States
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #3 on: January 01, 2016, 12:17:01 AM »
Finished restoration on the receiver and speakers.  the unit is a good performer.  Here are pics of the tuning indicator tube in the open position and the closed position that comes with a tuned in station.
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #4 on: February 11, 2016, 01:58:39 PM »
I've put up an antenna hidden in the soffit, and the shortwave reception is pretty impressive.  I have gotten radio Romania, China, Havana, Australia And a number of others with no English programming.  The amp gives decent fidelity with the FM receiver and Mp3 input.  It has really been fun playing with it.
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline Duffy

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Re: Magnavox Hepplewhite
« Reply #5 on: February 11, 2016, 02:55:43 PM »
That's a very nice piece you have there. Looks good.
CDN Doug

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #6 on: February 12, 2016, 04:55:30 PM »
Thanks!
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #7 on: March 06, 2016, 06:34:19 PM »
Here is a pic of the 2 10 inch field coil speakers they are driven by a 22 watt push pull amp.  There was a bit of abrasion damage on one speaker.  I put a strong patch on the damaged area .  You can see it on the left.

"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #8 on: March 06, 2016, 06:38:02 PM »
Here is a schematic diagram of the receiver/amp. I changed the FM audio connectors to RCA jacks from the period multi pin connectors.

« Last Edit: March 06, 2016, 06:41:53 PM by 19and41 »
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #9 on: March 06, 2016, 06:45:13 PM »
and this is a schematic of the FM converter used with it.  Both this and the receiver/amp required replacement of all their paper and electrolytic capacitors.

"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #10 on: March 22, 2016, 05:12:25 PM »
I got a RFI line filter that has cut the amount of spurious noise on the radio.  I was able to get Radio Prague between 5 and 7 pm while it was still daylight.  Just as strong and clear as the nearby AM stations. 
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #11 on: September 07, 2016, 02:45:13 PM »
I finally went to Home depot and got a post driver and a 1/2" 8 foot ground rod and sank it below the antenna lead in then ran some #8 wire from it to the shielding of the RG-6 I lead the antenna in on.  This reduces the RFI on the noise floor and allows for greater sensitivity across the short wave and AM broadcast bands.  Radio Havana comes in like it was coming from Atlanta.    I have had to do a replacement of the 15Mhz oscillator trimmer as the creatures that rented the interior before I purchased the radio leaked a little on it.  Surplus Sales Of Nebraska had a good replacement in both size and value.  I still need to do an over the air adjustment on the antenna trimmers to accommodate the new ground setup.  This thing has been mighty fun to work with since getting it!
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #12 on: November 17, 2016, 05:46:01 PM »
I've been listening to it regularly, and I get good reception from stations in both Europe and Asia.  The ground made a good improvement in it's reception.  The main stations I get regularly are ABC Australia and Radio China.  Radio Slovakia and Radio Prague come in  very well in the early evening, among other stations.  Radio Havana has a few good programs as well.  This thing has been a lot of fun for a $50 initial investment, sold to raise money for breast cancer research.
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline 19and41

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Re: Magnavox Hepplewhite
« Reply #13 on: January 10, 2017, 08:51:03 PM »
The bad storm that passed through last weekend has apparently gotten moisture into the outdoor portion of the coax line to the antenna.  I am getting ground feedack on the antenna line.  It will need a disassembly and hot air treatment.  I messed up and didn't put synthetic grease into the grounding break I put into the antenna line.  Act in haste, repent in leisure.
"Any sufficiently advanced technology is indistinguishable from magic."
Arthur C. Clarke

Offline Phonesrfun

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Re: Magnavox Hepplewhite
« Reply #14 on: January 10, 2017, 10:48:38 PM »
Unfortunately, water in coax is pretty bad.  If it is significant, coax can act like a pipe and I have seen situations where water will actually drip out of the inside end!


Water also destroys the properties of coax, and can't really be dried out effectively.    You might be replacing it when the weather gets better.  I learned the hard way that one DOES NOT want to transmit using soggy coax.  It has a tendency to act like a short to final amplifiers.
-Bill G